Initial laboratory investigations revealed profound anemia (Hemoglobin (Hb) 2 g/dL), neutropenia, thrombocytopenia, and significant deficiencies in vitamin B12 and vitamin D. Serologic testing was positive for anti-transglutaminase IgA antibodies, and duodenal biopsies confirmed celiac disease (CD) (Marsh stage 3a), along with Helicobacter pylori gastritis. The gene discussed is GSTM1; the disease is anemia (phenotype).